Transition structure

ABSTRACT

A transition structure between two different restraint systems with different compliances set up along roads is configured such that the restraint systems are connected with each other, on the one hand, and, on the other hand, the system with greater compliance comprises damping elements ( 20   a - 20   i ) reducing the compliance section by section and being arranged on the side averted from the roadway.

The present application claims priority to European Patent Application No. EP 04 023 779.4, filed 6 Oct. 2004, which application is incorporated herein fully by this reference.

TECHNICAL FIELD

The present invention refers to a transition structure between two different restraint systems at streets, the restraint systems having different compliance.

BACKGROUND ART

Restraint systems alongside streets are subject to the standard DIN EN 1317-2 of 1998 which establishes various classes and test methods. Beside metal restraint systems, in particular guardrails, such made of concrete have proven to be efficient.

The stepped restraint system of EP-A-1 293 610 has proven to be particularly efficient. Further, significant stretches of main roads, freeways and highways are secured with restraint systems of metal.

The critical part is the transition from one restraint system to another, especially when these have different compliances.

The pre-standard DIN V ENV 1317-4 stipulates in which cases transition structures have to meet certain requirements and further have to be subjected to a complex test. If both restraint systems are made of concrete, a test is required only if the compliance differs by two degrees. With transitions from concrete to steel, a test is already required even if the difference is only one degree of compliance.

DE-A-37 42 356 describes a transition structure for transportation infrastructure, the transition being from a concrete restraint element to a guardrail made up from an almost perpendicular steel post and at least almost horizontal steel bar. In the transition zone between the restraint system of concrete and the metal guardrail, the two restraint systems overlap. Vertical pipes of different diameters are provided between the guardrail and the restraint system of concrete. The pipes are supposed to absorb energy in the event of a vehicle crash. This is a rather complex structure since the position of the individual pipes has to be clearly defined. Further, it has been found that the desired smooth transition of compliance cannot be realized with this system.

Thus, the disadvantage still exists that, should a car crash into the restraint system in the transition area, severe accidents may happen in the transition area between two restraint systems of different compliance. In particular, a kind of ramp forming can occur by which a vehicle may be thrown off the road.

It is an object of the present invention to provide a transition structure between two restraint systems of different compliance that allows for a simple realization of a secure transition.

SUMMARY OF THE INVENTION

According to the present invention, the object is solved by connecting the restraint systems in an abutting manner and by the fact that, especially on the side averted from the road, the system having the greater compliance comprises damping elements reducing the compliance section by section.

Preferably, the damping elements thus have different compliances in a transition area between the two restraint systems. The damping effect of the individual damping elements decreases starting from the restraint system with little compliance to the restraint system with greater compliance. Here, the transition area is that area in which the compliance changes, starting from the one restraint system to the other restraint system. Preferably, the restraint system with greater compliance, such as steel guardrails, for example, is provided in the transition area, i.e., it is continued up to the restraint system with lower compliance, such as concrete restraint systems, for example, with the compliance being respectively increased or decreased step by step in the transition area by providing damping elements arranged especially on the side averted from the roadway.

The damping elements preferably are cast concrete elements or the like that are, in particular, set immediately upon a roadway surface without any anchoring. The damping effect of the individual damping elements preferably depends on the mass inertia. It is particularly preferred that the cast concrete elements or the damping elements are of the same height and the mass inertia is varied by changing the width or depth.

Preferably, the height of the individual damping elements corresponds to at least the height of the restraint system with greater compliance. This is advantageous in that the restraint system with greater compliance is deformed upon a vehicle or the like crashing thereon, whereby it is ensured that the metal guardrail, for example, is pushed against the damping elements and the guard rail does not slide over the damping elements.

Preferably, the damping elements are made of increasingly shorter parts of the restraint system with lower compliance. The shorter the parts of the restraint system with lower compliance, i.e. the restraint system of concrete or steel concrete, the easier they can be displaced sideward since they are preferably not anchored in the ground but only set thereon. Thus, the present transition structure from the system with lower compliance to the system with greater compliance, such as a metal guardrail, for example, provides a smooth transition.

Preferably, the individual damping elements are not connected with each other. In particular, such damping elements are spaced 5-50 cm apart. It is particularly preferred that the distance between adjacent damping elements increases in the direction of the restraint system with greater compliance. By providing such distances, the intentional displacement of the individual damping elements on the road surface, which causes the damping, is ensured.

Whereas, for example, the restraint system of EP-A-1 293 610 is connected over long distances and can therefore be displaced laterally only by very high loads, shorter pieces made from the same material can be displaced more easily. When these are arranged behind the metal rail or the guardrail of the adjoining steel structure with great compliance, they result section by section or almost smoothly in greater compliance up to the portion in which only the system with greater compliance is provided.

Of course, this structural principle may also be applied to the transition from a compliant system to a less compliant system. In this instance, increasingly longer damping elements of the system with lower compliance are provided at the end of the system with greater compliance up to the point where the two systems are connected in immediately abutting relationship.

Thus, a simple structure is proposed which, after corresponding preliminary tests, can be used generally and may reduce the very expensive tests to a few preliminary tests.

In particular, the present transition structure has the advantage that the optimum length of the transition structure and the dimensioning as well as the positioning of the damping elements can be determined by preliminary tests with conventional restraint systems. In later reproductions, it is then possible to calculate these on the basis of the preliminary tests so that no new test is required.

BRIEF DESCRIPTION OF THE DRAWINGS

The following is a detailed description of the present invention by means of a preferred embodiment and with reference to the accompanying drawing.

In the Figures:

FIG. 1 is a schematic illustration of a transition structure, and

FIG. 2 is a schematic front view of the transition structure.

In the embodiment illustrated, a restraint system with great compliance comprises a plurality of concrete restraint elements 10 set side by side on a road surface. These may be restraint systems sold by the applicant under the name Safetybaer H2 or Safetybaer H4, for example.

In the embodiment illustrated, a restraint system with great compliance comprises two safety rails 12 or metal guardrails. The first restraint element 10 with respect to the transition area 14 is covered at least partly by the two safety rails 12. For this purpose, the restraint element 10 has a recess 16. The recess 16 is formed such that it substantially corresponds to the depth of the safety rails so that these do not protrude beyond the front side 18 of the restraint element 10. Both safety rails 12 are connected, e.g. screwed, to the restraint element 10 in the area of the recess 16.

In the transition area 14, a plurality of damping elements 20 are provided behind the safety rails 12 on the side averted from the roadway. The individual damping elements 20 a-20 i have different damping effects. To reduce production costs, the outer shape or the cross section of the damping elements 20 corresponds to the shape of the restraint element 10. The width of the damping elements 20 decreases from the damping element 20 a, which is arranged immediately beside the restraint element 10 with lower compliance, to the damping element 20 i. In the embodiment illustrated, the damping element 20 i is the last and narrowest damping element which is adjoined by the restraint system with great compliance.

The individual damping elements 20 a-20 i are arranged on a foundation so that the damping elements 20 a-20 i can be displaced in the transition area 14 in the direction of the arrow 22 (FIG. 1) in the event of a car crashing in.

The individual damping elements 20 a-20 i occurs on the surface 28 of a foundation. The foundation may be a concrete foundation or the like.

To avoid mutual jamming or blocking of adjacent damping elements 20 a-20 i, the same are respectively arranged at a distance 24 from each other. 

1. A transition structure between two restraint systems with different compliances, wherein the restraint systems are connected in an abutting manner and, on the side averted from the roadway, the restraint system having the greater compliance comprises a plurality of damping elements reducing the compliance section by section.
 2. The transition structure of claim 1, wherein the damping effect of the individual damping elements decreases from the restraint system with lower compliance towards the restraint system with greater compliance.
 3. The transition structure of claim 1, wherein the damping effect is determined substantially by the mass inertia of the individual damping elements.
 4. The transition structure of claim 1, wherein the damping elements are cast concrete elements.
 5. The transition structure of claim 1, wherein the damping elements rest unanchored on a road surface or a top surface of a foundation.
 6. The transition structure of claim 1, wherein the damping elements are increasingly shorter parts of a restraint system, starting from the restraint system with lower compliance towards the restraint system with greater compliance.
 7. The transition structure of claim 1, wherein the damping elements at least have the height of the restraint system with greater compliance.
 8. The transition structure of claim 1, wherein adjacent damping elements are spaced at 5-50 cm from each other.
 9. The transition structure of claim 8, wherein the distances increase starting from the damping element with lower compliance towards the damping element with greater compliance. 